This invention relates generally to filter assemblies and, more particularly, to various embodiments of a filter housing assembly for use in compressors such as oxygen concentrators and other medical applications in the home care medical equipment industry.
Oxygen concentrators are commonly used in the care of respiratory patients, particularly, in the home care environment, to provide sufficiently high purities of oxygen to the patient without using high pressure tanks or liquid oxygen. Oxygen concentrators utilize ambient atmospheric air as their source of oxygen in conjunction with an absorption system to separate oxygen from the other gases found in the air and to provide that oxygen in concentrated form to the patient. Atmospheric air typically includes approximately 80% nitrogen and 20% oxygen. The various types of absorption systems used in oxygen concentrators generally include molecular sieve beds for separating the gas mixture into an oxygen portion and a nitrogen portion. Nitrogen is absorbed by the molecular sieve beds when under pressure and is retained in such sieve beds until subsequently purged. Typically, two sieve beds are utilized so that as one sieve bed separates nitrogen from the oxygen, the other sieve bed is simultaneously purged of the nitrogen absorbed during the prior separation cycle. This separation process is accomplished through an appropriate absorbent material utilized in the sieve beds such as special granulated materials, for example, Zeolite® granules, which selectively absorb the oxygen from the compressed air passing through the sieve beds.
Typically, atmospheric air is drawn into an oxygen concentrator from the ambient environment. Such ambient air is then passed through a filter assembly to remove dust and other contaminants, and the filtered air is then pressurized by a compressor for introduction into the absorption system or molecular sieve beds. Once the compressed air is introduced into one of the molecular sieve beds containing the granulated absorbent material, nitrogen is selectively absorbed leaving the residual oxygen available for patient use. After a predetermined period of time, the supply of compressed air is automatically diverted to the second molecular sieve bed where the process is repeated enabling the output of oxygen to continue uninterrupted. While pressure in the second molecular sieve bed is increased, the pressure in the first molecular sieve bed is reduced to zero thereby allowing nitrogen to be released and returned to the atmosphere. The granulated absorbent material is then regenerated and made ready for the next cycle. By alternating the pressure in the two molecular sieve beds, a constant supply of oxygen is produced while the selected absorbent material is continually being regenerated. Oxygen concentrators typically produce an oxygen concentration usually in the range of 90-95%.
Use of an effective filtration system for purging contaminants from any liquid or gas is always important for a multitude of obvious reasons. Properly and effectively filtering the incoming ambient air before it is compressed and introduced into the molecular sieve beds of an oxygen concentrator is likewise important because effective filtration not only improves the overall efficiency of the oxygen concentrator but it also improves and increases the oxygen concentration provided to the patient. Routine maintenance also includes changing the air filters at regular intervals. As a result, easy access to the filter assembly, easy manipulation, removal and re-installation of the filter housing assembly, and improved filtration of the air passing through the filter assembly are important characteristics of any oxygen concentrator. Still further, the type and size of compressor associated with an oxygen concentrator determines the overall oxygen flow rate capacity as well as the level of noise produced by the system during operation. In general, large compressors required for providing higher rates of oxygen can be quite noisy.
It is therefore desirable to provide a filter housing assembly which improves the air filtration process to the molecular sieve beds, which is easily manipulated to change filter assemblies on a periodic basis, and which can reduce and dampen the overall noise level associated with the operation of an oxygen concentrator or other compressor assembly.
Accordingly, the present invention is directed to a filter housing assembly which overcomes one or more of the problems as set forth above.